The present invention relates to a device, a mounting process and an application of this device allowing measurings and/or servicings to be carried out in a well at the level of the surrounding formations.
The invention is notably applicable when measurings and/or servicings are to be carried out at the level of geologic formations crossed through by a well. In this case, the measurings performed may comprise recording the bottomhole pressure and temperature, measuring the electrical resistivity, as well as acoustic, nuclear measurings, etc. Perforating guns, completion tools or visual display cameras may also be used.
These measuring and/or servicing techniques are known by specialists and will not be described more in detail hereafter.
The present invention is particularly well suited for carrying out measurings and/or servicings in an oil production well comprising a drain strongly inclined with respect to the vertical or even horizontal.
Document U.S. Pat. No. 4,685,516 describes a well-known system for carrying out measurings or servicings in a well, comprising a metallic tubing coiled by plastic strain round a drum, an electric transmission cable being slipped into the tubing. Setting such a cable is problematic because, when the tubing is completely uncoiled, the cable must be pulled by a tool pumped in the tubing. Moreover, during coiling and uncoiling operations from the drum, the cable exhibits a longitudinal mobility since its diameter is smaller than the inside diameter of the tubing, which often causes elongations which may accumulate in loops inside the tubing and eventually damage the cable itself.
Patent FR-2,631,708 describes a known device for carrying out measurings and servicings in a well, which improves the technique by using a rod made of a polymeric material and incorporating the line. But the rod disclosed in this document presents the disadvantage of having such a rigidity that the diameter of the drum is too bulky. Moreover, this rod practically no longer allows fluid pumping.